Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Natural Ventilation and HVAC system Usage

asked 2022-02-07 18:32:56 -0600

prp92's avatar

updated 2022-02-08 09:19:57 -0600


Natural Ventilation (passive) and HVAC (active) are two major methods of ventilating the building. I have couple of questions about these two.

  1. If natural ventilation is active (open window), does the HVAC system still operate in Energy Plus simulation?

  2. Suppose my dual thermostat setpoint temperature is set at 20C for heating and cooling. My outdoor temperature is 15 C and my window is open. To maintain my thermostat temperature, my HVAC system needs to operate. Which Output:Variable should I use to calculate the heating load required to maintain my zone temperature at 20 C?


edit retag flag offensive close merge delete

2 Answers

Sort by » oldest newest most voted

answered 2022-02-07 23:45:22 -0600

hardik_gajjar's avatar

updated 2022-02-09 08:34:44 -0600


  1. Operation of Natural ventilation and HVAC will depend on the schedule that you'll assign in Schedule:Compact (or any other). Meaning, you can operate both as per your convivence. Generally speaking, HVAC system will demand more power when operated while keeping windows ON. Because when the windows are open, the indoor air temperature will get neutralized with outdoor air temperature by constant air mixing. Henee the HVAC system will demand more power to either cool down or warm up the zone air temperature to the setpoint.

  2. For heating/cooling demand output you can use : ZoneIdealLoadsZoneTotalCoolingEnergy or HeatingEnergy. This will give you output in Joules. And for Input, you can use HVACTemplate:ZoneIdealLoadsAirSystem.

edit flag offensive delete link more

answered 2022-02-08 23:30:52 -0600

silencetly's avatar

updated 2022-02-09 08:35:03 -0600


1、If natural ventilation is turned on, the air conditioning system will be turned on accordingly according to the setting of natural ventilation. Of course, it needs to set a parameter setting matching the air conditioning system and natural ventilation. can select Output:Variable or meter to calculate the heating load. If you encounter software problems at work, please contact me.

Wechat: xiang_zhong_meng

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools

1 follower


Asked: 2022-02-07 18:32:56 -0600

Seen: 255 times

Last updated: Feb 09 '22